The CAS Registry Mumber 871487-67-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,7,1,4,8 and 7 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 871487-67: (8*8)+(7*7)+(6*1)+(5*4)+(4*8)+(3*7)+(2*6)+(1*7)=211 211 % 10 = 1 So 871487-67-1 is a valid CAS Registry Number.